Xue Kong’s research while affiliated with Dalian University of Technology and other places

Integrated energy systems (IESs) are essential for enabling the energy transition in communities and reducing CO2 emissions. This paper proposes a novel IES that combines photovoltaic (PV) and solar thermal energy with coordinated electrical and thermal energy storage to meet the energy demands of residential communities. The system also incorporates hydrogen production for fuel cell vehicles. A dual-objective optimization model was developed, minimizing both economic costs and CO2 emissions. The system’s performance was evaluated using data from a case study in Dalian, which showed that the IES successfully reduced the annual total cost and CO2 emissions compared to conventional systems. The key findings showed that PV electrolysis for hydrogen production provides both economic and environmental advantages. The system’s integration of solar thermal energy offers higher economic efficiency, while PV energy supplies enhance coordination. Additionally, carbon trading prices effectively reduce emissions, but excessively high prices do not always lead to better emission outcomes. This study introduces a comprehensive, multi-energy approach for optimizing the energy supply, contributing novel insights to the field of sustainable energy systems.

The high level of integration of distributed generation systems (DGSs), especially distributed wind and solar, significantly affects the flexibility and controllability of the power system. Aggregating local DGSs and shared energy storage systems (ESSs) within an energy community offers an economically and environmentally viable solution. However, the coupling of shared ESSs with the energy community, while considering subjectivity, is often overlooked. Therefore, this study introduces a two-layer optimization framework that enables DGSs to trade energy freely, voluntarily, and independently and to share ESSs within the energy community, considering participants’ subjectivity. The upper layer optimizes the size of shared ESSs, while the lower layer, structured as a two-layer model, simulates participant interactions. The numerical case shows that, compared to DGSs operating individually, the shared ESS case indicates that community self-sufficiency and self-consumption rates increase by 16.22% and 21.98%, respectively. Additionally, the annual operating cost is reduced by approximately 27.10%, and CO2 emissions are decreased by about 33.24%. Considering DGS’ subjectivity, the self-sufficiency and self-consumption rates are 3.04% lower, and the total operating costs and CO2 emissions are 3.26% and 6.86% higher, respectively.

The optimal utilization of an energy storage system (ESS) is key to transforming energy systems from coal to renewable base. This study proposed a multi-objective optimization method for designing energy systems, a multi-criteria evaluation method for analyzing ESS and its suitability in an energy system, and a novel ESS scheduling strategy. A grid-connected energy system including wind power, photovoltaic, and ESSs was considered for responding to electricity demands, wherein multi-criteria assessments for technical, economic, and environmental aspects, with total cost and self-sufficiency as the objective functions, were implemented. The results demonstrated the significant potential of ESS through comparisons of performance of energy systems with and without ESS. In fact, self-sufficiency and self-consumption improvement can reach 21.57% and 32.84% respectively, and the non renewable primary energy consumption and CO2 emissions both up to 60.63% could be avoided. This study provides practical guidance for preliminary energy system analysis and construction planning as well as technical support for policy makers when deciding on project construction.

An important strategy to stimulate renewable energy consumption is adherence to renewable portfolio standard (RPS), which has cost advantages over feed-in tariff (FIT). China published its provincial RPS goals in 2018 and, since then, it has been pressurizing provinces to realise the goals. This study develops a mid-to long-term optimisation model for the area served by the China Southern Power Grid Corporation (CSPGC) based on power-plan constraints and RPS goals for 2016–2030. The results indicate an optimal method for the five provinces in the CSPGC area to achieve their RPS goals based on the power-plan constraints till 2030. For electricity generation, wind power development should precede solar power development; further, hydropower development is particularly significant for the region. To facilitate electricity transmission, the construction of transmission lines between Guangdong and Yunnan should be prioritised. In electricity trading, RPS policy implementation will cause Guangdong to buy more electricity from western provinces, aiding the completion of the West–East Electricity Transfer Project. Moreover, in the CSPGC area, RPS policy implementation will not significantly affect the total electricity supply cost due to the development of low-cost hydropower in the region.

In today's China, the reverse distribution of electricity resources and electricity demand makes large-scale and long-distance transmission of electricity inevitable, resulting in the problem of electricity allocation optimization. To address this problem in the region covered by the China Southern Grid (CSG), the paper establishes an optimized model for electricity generation and interprovincial trading strategies in southern China. Based on data from 2015, this paper simultaneously optimizes electricity generation and interprovincial trading strategies in each of the five provinces. The result shows that interprovincial trading in the CSG-served area can yield significant energy, economic, environmental and interconnection benefits. It can reduce the power supply cost and environmental pressure in Guangdong province, help make Yunnan province a hydropower base in China and a thermal power base in southern China, facilitate the completion of the “West-to-East Power Transmission” project, and partly resolve the issues raised in each province's 13th Five-Year Plan as well as the problem of optimizing electricity allocation in the region covered by the CSG.